Short Circuit and Coordination Studies
Performance Services
Proper systems evaluation for
improved protection
The electrical distribution system is the
foundation of your entire operation. Its
reliability is challenged every time an
expansion, reconfiguration, additional
load, or upgrade takes place.
Short circuit and coordination studies
help manage these complexities by
ensuring that the protective device
closest to an overload or short-circuit
condition is the one that operates to
quickly isolate a failure.
The results of these studies allow for
proper protective device settings
thus helping critical facilities maintain
a safe, reliable, and efficient electrical
distribution system.
Benefits:
„„ Minimize system downtime and
nuisance device operations
„„ Avoid equipment damage or
failure through increased system
protection
„„ Isolate faulty circuits without loss of
power to other parts of the system
„„ Identify corrective action for underprotected equipment
„„ Ensure safety of personnel
Ensure minimum service interruption and equipment
protection with short circuit and coordination studies
As electrical distribution systems change, it’s important to ensure continued
protection for equipment and employees. A short circuit and coordination study
can ultimately help critical facilities avoid accidents, productivity losses, costly
fines, and higher insurance costs.
A coordination study is an evaluation of a system’s protective devices, such as
relays, fuses, and circuit breakers, and the circuits they protect. A coordination
study determines how long equipment can sustain operation without damage or
failure by comparing the operating levels and times of protective devices to the
withstand levels and times.
The goals of these studies are to provide power transformers, switchgear,
substations, motor control centers, panelboards, and other electrical equipment
with required protection while selecting appropriate types, ampere ratings,
and device settings to ensure minimum service interruption under overload and
short-circuit conditions.
Our short circuit and coordination studies include:
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Data collection
Power system analysis
Report of findings including device settings
Updated single-line diagram
Short Circuit and Coordination Studies
Performance Services
Data Collection
Summary
Power System Analysis
With short circuit and coordination studies, customers get
a better understanding of how their often-changing
electrical distribution system currently operates. The
coordination and settings of protective devices are
thoroughly analyzed, and based on the findings, customers
are able to improve protection for equipment, personnel,
and their business as a whole.
In order to determine the appropriate types, ampere
ratings, and device settings, Emerson’s technical staff will
review an up-to-date single-line diagram of the electrical
distribution system. Ideally, the single-line will provide
equipment ratings, wire sizes, lengths, etc. If a current
single-line diagram and relevant data is not available, then
the engineer will need to collect this data to perform the
study. The data collection process is an ideal time to update
the single-line diagram because all pertinent information
will be accumulated.
Once data is collected on the electrical distribution system,
Emerson then utilizes power systems software including
SKM, ETAP, and others to assist with analysis. The computer
model helps Emerson engineers determine optimum
settings for all adjustable devices, ensuring
proper coordination.
Report of Findings
Following comprehensive computer-based analysis, a report
of all the findings is carefully documented in an electronic
and/or paper report that includes:
If circuit breakers or other protective devices are set too
low, they may trip unnecessarily causing critical loads to be
dropped. Set too high and the protective device closest to a
failure may not trip causing another device further upstream
to trip—resulting in an outage to a much larger part of
the electrical distribution system and possibly a complete
blackout of the business-critical facility.
Ordering Information
To learn more about this service and other Emerson
Network Power solutions, visit EmersonNetworkPower.com
or call 1-800-LIEBERT (543-2378).
„„ Clear tabular printouts of the suggested settings for all
adjustable devices
„„ Time-current curves of the protective devices illustrating
the resulting protection and their coordination
Updated Single-Line Diagram
Also included with the report of findings is a computer
generated single-line diagram illustrating devices,
equipment, system connections, and short circuit levels.
This schematic supports future engineering services for
performance optimization and enhanced safety, and is
essential for ensuring critical facilities are compliant with
code regulations.
Emerson Network Power
Liebert Services
1-800-LIEBERT
EmersonNetworkPower.com
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